1. Field
The present invention relates to a dental handpiece for root canal treatment and in particular for measuring the length of a root canal.
2. Description of Prior Art
Such a handpiece is known from European Patent Application EP 1,642,547 A1 (the '547 application), which is incorporated herein by reference. The handpiece disclosed in the '547 application has a device for transmitting electrical measurement signals of the root canal length measurement, which is formed by the elements for transmitting the driving motion, in particular by the drive shafts, the gears and gearwheels of the handpiece.
Transmission of the electrical measurement signals of the root canal length measurement by the mechanical transmission elements has the advantage that existing components can be used for conducting the measurement signal. However, it is a disadvantage that the quality of the signal transmission is sometimes low and in particular that some measurement signals are lost, especially in the area of the interfaces between the elements for transmission of the driving motion, e.g., between individual shafts or shaft parts.
There is thus an advantage in a handpiece for root canal treatment with a device for transmission of the measurement signals which is formed by the elements for transmitting the driving motion such that an improved secure signal transmission and in particular a reduced loss of measurement signals during the signal transmission is ensured. In addition, a method for manufacturing a handpiece with an improved signal transmission would also be advantageous.
Another disadvantage of the handpiece described in the '547 application is that further conduction of the measurement signals takes place at the connection end of the handpiece via the driving element to a shaft of a connecting part, e.g., a coupling, connected thereto. There is thus another interface between shafts that are detachably connected to one another and subject to some play, resulting in inadequate signal transmission and loss of measurement signals. In addition, conducting the measurement signals further via the dog shaft portion of the handpiece requires a suitably complex design of the connecting part with electrical insulation of the shaft of the connecting part.
Thus, it would be advantageous to provide a handpiece for root canal treatment which will allow an improved conduction of the measurement signals to the connecting part.